1. Field of the Invention
The present invention relates to a bladder and an accumulator using the same, and, in particular, to such an accumulator of the type provided with a thin wall section which prevents the concentration of stress produced near the base of the bladder mounting flange, and reliably prevents variable stress from being exerted on the mounting flange base, such that the problem of the thin wall section allowing gas to pass through does not arise.
2. Description of the Related Art
As shown in FIG. 7, a conventional accumulator bladder is formed from elastic material, such as rubber, into the shape of a bag, with a mounting flange 23 provided along an opening 25m. The bladder 25 is air-tightly attached to a container main body 24 by means of the flange 23. As shown in FIG. 8, the bladder 25 is formed to an overall thickness equivalent to the thickness of a base 26 of the mounting flange 23, W.sub.0, and the thickness of the flange 23, W.sub.1, is made larger than the above-described base 26 thickness, W.sub.0.
When accumulated liquid in the container main body 24 is discharged from an opening 28 at a high speed, the bladder 25 expands rapidly, so that a variable stress is exerted on the base 26 of the mounting flange 23.
This often results in breaking of the base 26 of the mounting flange 23 of the bladder 25 due to fatigue.
It is thought that this problem may be overcome by forming the bladder into one having a larger overall thickness than the the base 26 of the mounting flange 23 (having a thickness of W.sub.0).
However, although this prevents variable stress from being exerted on the base 26, it gives rise to the problem of increased gas transmission.
Consequently, sealed gas leakage occurs, which results in reduced capacity of the accumulator ACC within a short period of time.